Faculty Bibliography

Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes.

A number of archaeological studies have used chemical analysis of preserved, human biological tissues to assess the potential exposure of historic figures and ancient populations to heavy metals. Accurately assessing historic levels of heavy-metal body burden for these individuals based on analysis of remnant soft-tissue, hair and bone collected from preserved human remains is often complicated by the potential for post-mortem chemical modifications and contamination of the body and burial site. This study employs high-resolution, synchrotron-based elemental X-ray fluorescence mapping, tomography and absorption spectroscopy of human remains collected in an archaeological context in an effort to discriminate between heavy metals such as mercury and lead that may have been incorporated through either endogenous or exogenous processes. These methods were used to analyze bone and hair samples from Ferrante II of Aragon, King of Naples (1469-1496) and Isabella of Aragon, Duchess of Milan (1470-1524). These individuals are likely to have been exposed to generally similar levels of heavy metals in their lifetime, would have been embalmed using similar methods and the post-mortem exposure to contaminants is likely to have been similar. Although the remains from both Ferrante II of Aragon and Isabella of Aragon contain high amounts of mercury and lead, the high-resolution and sensitivity synchrotron microprobe techniques employed in this study provide insight in to the likelihood these metals were incorporated pre-mortem rather than as ante-mortem contaminants. Although synchrotron X-ray fluorescence mapping and tomography are generally consistent with measured mercury from Isabella hair samples being endogenous in nature, the high levels of mercury seen in Ferrante II's remains are most likely related to post-mortem embalming of the corpse. However, application of microfocused X-ray fluorescence compositional mapping and lead L-2 edge X-ray absorption spectroscopy to bone samples collected from Ferrante II show that the measured lead is likely endogenous and the result of in-life exposure to this heavy metal. (C) 2014 Elsevier Ltd. All rights reserved.